1. Field of the Invention
The present invention relates to a brake device, and more particularly to an anti-lock brake system for a bicycle.
2. Description of the Prior Arts
A conventional brake device for a bicycle generally includes a pair of brake shoes and a brake arm, the brake shoes are coupled to both legs of the brake arm and then the brake arm is mounted to the rear and/or front fork of a bicycle with the brake shoes standing oppositely at both sides of the wheel rim of the bicycle. The brake shoes are employed to press against the wheel rim from both sides by virtue of the brake arm and a friction to be generated to stop the rotation of the tires. This kind of brake device has been commonly used in nowadays, however, there are still some shortcomings need to be improved:
In event of an emergency brake, the braking force is greater than the friction force of the tires due to a great force applied by the rider to press on the hand brake in order to stop the rotation of the tires, which will generate a dead lock of the tire in a sudden and result in a skidding and overturning of the bicycle and hurt of the rider.
A buffering device targeting at the solution of the above problem is shown in FIG. 1 including: a brake shoe holder 10, the brake shoe holder 10 to be mounted to a brake arm by virtue of a connecting rod 11 coupled at a side opposite to the wheel rim of the tire and has a pair of protruding edges opposite to each other defining a space for accommodating a sliding piece 17 therein, furthermore, the brake shoe holder 10 defining a threaded hole 12 at a first end for engaging a bolt 13 and a recess 14 at a second end for accommodating an elastic member 15, a brake shoe 16 to be engaged in the sliding piece 17 and the sliding piece 17 has a first end connected to the elastic member 15 and a slot 18 defined at a second end engaging with the bolt 13 for preventing the sliding piece 17 from sliding out from the brake shoe holder 10, in such a manner, taking use of the slide of the sliding piece 17 in the space of the brake shoe holder 10 and the elastic member 15 to buffer a friction of the brake shoe 16 while it pressing against the wheel rim the tire. Although this braking device has been commonly used, there are also some shortcomings need to be improved:
First, this braking device is too complicated that the brake shoe holder 10 not only needs a pair of protruding opposite edges to define a space for the receiving and slide of the brake shoe 16 therein but also the brake shoe 16 should be engaged in the a sliding piece 17 having a slot 18 for engaging a bolt 13, in this case, it""s not only complicated in assembling process but the production cost is increased as well.
Second, there is only a very short distance (about a 1 mm in distance) for the slide of the brake shoe 16 in the brake shoe holder 10 according to this device, which is not long enough for buffering the friction generated from the braking motion and accordingly a rider is not able to control the bicycle effectively.
Third, in accordance with the brake device for a bicycle, the brake shoe only has a very short contracting distance while a braking motion being operated and it will be contracted to an end thereof and will not return to the original position till the rider release the handle brake, thereby, there will be a great friction caused from a part of the tire and the ground and do a great harm to the tire.
Fourth, in accordance with this conventional brake device for a bicycle, the brake shoe holder 10, the recess 14, the brake shoe 16 and the sliding piece 17 all move in a straight line, however, the tires of the bicycle do rotational movement, in such a manner, a stress of the tire is generated from the friction of the brake shoe 16 while a braking motion being operated which can""t be transmitted completely to the elastic member 15 and a part of it can""t be counteracted (which is perpendicular to a direction of the movement of the brake shoe 16), as a result, the brake shoes 16 is not allowed to move smoothly and freely in the space of the brake shoe holder 10 and great frictions and collisions will be caused in the related parts.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional anti-lock brake system for a bicycle.
In accordance with one aspect of the present invention, there is provided an anti-lock brake system for a bicycle having sliding assembly (having a brake shoe therein) and a plurality of springs defined in a brake shoe holder in turn, an acting direction and location of the springs are corresponding to that stress direction of the brake shoe, the brake shoe is partially engaged in the brake shoe holder, a bottom of the brake shoe holder and a connecting side of the sliding assembly is correspondingly in gradient formed and both of them to be abutted against each other and slantingly formed outwardly in accordance with the direction of the rotation of the tires of the bicycle. (For an alternative that a plurality of sliding members also can be defined between the bottom of the brake shoe holder and the sliding assembly and in addition, an abrasion-resistant member can be defined at the bottom of the recess of the brake shoe holder). In such a manner, which not only can buffer a braking friction generated from an emergency brake but also prevent a great friction from being caused in the related parts of the braking device.
The primary objective of the present invention is to provide an improved anti-lock brake system for a bicycle, which is not only capable of buffering a braking friction from being generated from an emergency brake but also preventing a great friction caused in the related parts of the braking device.
Another objective of the present invention is to provide a simple anti-lock brake system for a bicycle, which is not only reduce the production cost to the least but also simplify the assembling process.
A further objective of the prevent invention is to provide an improved anti-lock brake system for a bicycle allowing a free and smooth slide of the sliding assembly in the brake shoe holder and the quick return of the brake shoe to the original position so as to provide a smooth braking operation.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which shows, for purpose of illustrations only, the preferred embodiments in accordance with the present invention.